Don't die on fetching problems.

lib/pleroma/web/ostatus/ostatus.ex

@@ -300,6 +300,7 @@ def fetch_activity_from_html_url(url) do
   end
 
   def fetch_activity_from_url(url) do
+    try do
       with {:ok, activities} when length(activities) > 0 <- fetch_activity_from_atom_url(url) do
         {:ok, activities}
       else
@@ -307,5 +308,10 @@ def fetch_activity_from_url(url) do
                 {:ok, activities}
               end
       end
+    rescue
+      e ->
+        Logger.debug("Couldn't get #{url}: #{inspect(e)}")
+        {:error, "Couldn't get #{url}: #{inspect(e)}"}
+    end
   end
 end